This invention relates to removing excess or undesirable solder from printed circuit boards, clearing it from through-holes in such boards, and generally providing a relatively uniform solder level where appropriate on such boards. (For convenience herein such a printed circuit board will be generally referred to as a PCB.)
Of these prior systems within the knowledge of the herein inventor, all such systems rely upon covering the PCB with flux and then dipping it into hot liquid solder. These processes generally leave an uneven or undesirably thick layer of solder on the PCB which plugs through-holes used to connect the two sides of the board. The through-holes are typically required to be clear of plugging so that the leads of various electronic components may be inserted therein.
Various methods of leveling the solder and removing the excess, including that located in the through-holes, have been previously described in the prior art. Such methods involved the spraying of hot solutions or hot gases onto the PCB. More specifically, those systems relying on hot gases sprayed in air typically produce non-uniform through-holes and tend to be sufficient in removal of short circuit paths. In those systems relying on hot solutions sprayed in air, the resulting solder thickness left on the PCB is often inadequate for industry standards.
Such difficulties arise from the inability of such systems to adequately control the direction, flow shape, and flow rates of the medium used therein. The herein invention presents a solution to such problems, as well as providing for improved environmental control.